Question

Determine whether the claim stated below represents the null hypothesis or the alternative hypothesis. if a hypothesis test is​ performed, how should you interpret a decision that​ (a) rejects the null hypothesis or​ (b) fails to reject the null​ hypothesis? a researcher claims that the standard deviation of the life of a certain type of lawn mower is at least 2.8 years.

Answer 1

This would be the null hypothesis. 

A decision to reject this hypothesis means that the mean life span is less than 2.8 years.  A decision to fail to reject this hypothesis means that the life span is indeed at least 2.8 years.